Induction controller



Feb. 14, 1933. R. H. BARBOUR 1,397,415

INDUCTION CONTROLLER Filed April 25 1951 3 Sheets-Sheet l Mk MW ATTOR/VEXS Feb. 14, 1933.

R. H. BARBOUR 1,897,415

INDUCTION CONTROLLER Filedjpril 25 1931 3 Sheets-Sheet 3 Patented Feb. 14, 1933 mm: my maroon, or LONDON, momma INDUCTION oon'rnoma Application filed April 25, 1831, Serial No.

This invention relates to induction controllers, wherein the electromagnetic relationship betwen stationary primary and sec ondary windings is varied by moving a magnetic member or rotor. The induction controller may conveniently be provided with a fixed magnetic framewor or yoke, having slots on opposite sides carrying'the primary windings, and other slots on opposite sides to one another, but with their axis at an angle, usually 90 degrees, from that of the primary slots, carrying the secondary windings and with a magnetic member rotatable through about 90 degrees, having pole faces which cause the magnetic flux induced by the primary windings to pass through the secondary winding in one or other direction, or intermediatel Accor ing to the present invention, the

rotor of the induction controller is arranged to carry conducting members which provide at least two closed paths for electric currents within the magnetic mass of the rotor. These paths are so arranged as to have no magnetic interaction with flux passing directly through the rotor from pole face to pole face parallel to the magnetic axis of the rotor, but to be interlinked with flux passing transversely across the magnetic axis of the rotor. The conductive members may consist of pairs of conducting rods for example of copper, extending along the rotor parallel to its rotational axis and connected together in pairs by bridge pieces at opposite ends of the rotor. However, greater conductivity in the closed or short-circuited paths may be obtained by providing actual plates of conducting material extending along the rotor in planes parallel to that containing the magnetic and rotational axes. It is convenient then for the rotor to have its laminations of magnetic material also extending in planes parallel to that containing the said axes. It is preferred to use a symmetrical arrangement with conductive plates placed on opposite sides of the central plane of the rotor and equally spaced from that plane, and in fact, a satisfactory mechanical construction with a good performance is obtained by having a zone of such plates on opposite sides ofthe 532,908, and in Great Britain May 17, 1830. e

In such a case,

ondary windings tend to drive transversel across the rotor, that is to say, not linked wit the primary windings. In the neutral position of the rotor, all the flux through the secondary windings is linked with the conductive paths; in the extreme position none is linked with them and in the intermediate positions of the rotor all the flux throu h the secondary windings which is not linke with the primary windings is linked with some at least of the conductive paths. It will be understood that in the above statement flux leakage, outside the magnetic paths provided has been neglected.

The reason why at least two conductive paths are provided in the rotor is that in the positions etween the neutral position and either extreme position, some of the primary flux makes a limited passage transverse to the magnetic axis of the rotor.

Thus, in the novel arrangement accordin to this invention in every position of the rotor, whatever portion of the flux linked with the secondary winding is not also linked with the primary winding, is linked with sufiicient closed conductive aths to reduce the inductance of the secon ary winding to a low figure.

A good mechanical structure may be obtained by employing a rigid central steel plate or web to serve as a foundation support for the conducting plates and lamina tions. This arran ement also has the advantage that it enables end bearings for the rotor spindle to be formed merely by castv .to S while all S is intercepted by one or other 'remo'ved ary' windings are not ing sleeves about the ends of the said central late. P For a three-phase induction controller, groups of laminations are placed in succession alon the axis of the rotor, and those associate with each phase are preferably se arated from one another.

n order that the invention may be clearly understood and readily carriedinto efiect particular examples will now be described with reference to the accompanying drawin? in which r 0 i res 1, 2 and 3 are merely diagrams, whic show the rotor within itsstator in three difierent positions;

Figure 4 is a side elevation of one form of rotor constructed in accordance with the invention;

Figure 5 is an end elevation of. the rotor from the left of Figure 4 with certain parts Fi re 6 is a side elevation of an alternative orm of rotor; and

Figure 7 is an end elevation, with the rotor in the neutral position within the stator, the rotor bein shown in section on the line VII- -VII in igure 6.

In Figures 1, 2 and 3 the stator S is shown built up of ma netic stampings and has four pole pieces 8, S S. The primary winding X is carried in diametrically opposite slots P between the pole pieces, and the secondary winding Y is placed at right angles to it in the slots Q.

In Figure 1 the rotor It is shown so that its pole faces lie substantially opposite the poles S and S. In this position, the primar and secondary windings are fully interlinked, all flux (other than leakage outside the provided magnetic paths) passing through one also passing through the other from the pole S to the pole S. The conductive rings have no effect on this flux.

In Figure 2 the rotor R is shown in the neutral position. The primary and secondinterlinked. The primary flux has unimpeded paths through the rotor from poles S ms and from oles S the secondary flux is intercepted by both the closed circuits through the rotor conductors 4. In the position shown in Figure 3 there are unimpeded paths through the rotor for the primary flux from poles S to S, S to S and S to S while secondary flux from S to S and from S to of the closed circuits in the conductors 4, and secondary flux from S to S is linked with the primary. The path between S and S is to a limite axis. It will be noted is moving from the positionshown m Figure 2 to that shown in Figure 3, the two paths along the edges of the rotor are ceasing to be efi'ective while the path down the (1 12b on each side extent transverse to the rotors magnetic that when the rotor middle of the rotor is tive. Most flux passes down the middle of the rotor in the position shown in Figure 1.

Referring to Figures 4 and 5, the induction controller spindle 1 is shown square a one end at 1a so that a handle may be attached for rotating the rotor. This spindle carries the rotor assembly comprising soft iron transverse stampings 2 provided with slots 3 to receive rods 4. At oneend ofthe rotor a copper plate 5 unites the ends of all four of the coper rods, while at the opposite end of the rotor two bridge pieces 6, only one of which is shown in the drawings, serve to connect the rods 4 in pairs. Insulating, sleeves 7 surround the rods 4 and mica washers 8 insulate the bridge pieces 6 from casting 10 (which assists to hold firmly the stampings 2 in order to avoid the formation of close circuits through the undesired pairs of rods 4. The result is that there is one closed circuit on one side of the rotors magnetic axis through upper and lower rods 4 through the bridge pieces 6 at one end of the'rotor an the plate 5 at the opposite end. There is a similar closed circuit at the opposite side of the magnetic axis of the rotor.

The construction may be slightly modified by replacing the plate 5 by a pair of bridge pieces similar to those shown at 6 and menated by mica washers su h as 8. It is preferred for the conductingrods 4 to be placed at about a third or a quarter of the width of the rotor from the edge of the rotor. The stampings are recessed on either side to receive a copper plate 9. These copper plates 9 help to reduce leakage of fi'ux outside the rovided magnetic paths and are particularly useful in the positionshown in Figure 1 when they are located immediately opposite the stator poles S, S. In this position, the primary and secondary windings are both magnetizing the poles S and S in the same sense and a strong field would be set up but is restrained by currents induced in the plates 9. Thus the currents inducedin the plates 9 oppose the magnetizing eifect of the stator windings whereby the selfrinductance of the latter isreduced.

In the form of construction shown in Figures 6 and 7 the rotor R is built up about a thick central steel plate 10 running along the rotational axis. In the particular construction shown in these figures there is on either side of the plate 10 a layer 11a and 11b of magnetic laminations, for example of soft iron. These are followed by a zone 12a, consisting of laminations which are alternately magnetic material. Again by a layer 13a, 13b of the magnetic plates and finally, the rotor is finished by providing two thick copper plates 9 which serve the same purpose as the copper plates 9 in Figures 1 to four copper conducting of copper and of the this is followed becoming more effec- 5. The whole rotor assembly is mechanically by insulated transverse in Figure 6 the rotor is arranged for a threephase induction controller with three groups of stampin s seen at A, B, C, a d with two assembly bits 14 per phase.

or the purpose of mounting and rotation, the central steel plate 10 is tapered d width towards the ends at 15 and gun metal bearing sleeves 16 are cast on the ends.

construction to that shown in Figures 3 to 5 the primary winding being t e secondary winding at Y.

I claim said rotor including a plurality of low resistance paths for electric currents arranged so that magnetic flux linked with said sec either with said primary'winding or with said closed paths.

2. Induction controller apparatus, compris'ng in combination, a stationary magnetic structure, primary. and secondary windings mounted thereon, a magnetic rotor mounted a conductmgrods carried gether said rods in pairs. I 7

3. Induction controller apparatus, com+ prisin in combination, a statlonary magnetic structure, primary and secondary wmdmgs by a plate of electrically conducting material extending parallel to the axis of rotation and arranged so that magnetic flux ed for movement relatively to said windings and mcludm a set of laminations o magnetic materia extending axially of 5. duction controller apparatus, comprising in combination a stationary magnetic structure, primary and secondary windings mounted thereon, amagnetic rotor -tral steel web ratus,

said iotoli-mmounted for movement relatively to said windings and including a set of lam nations of magnetic material extending axlall of said rotor and a plurality of lates of con ucting material carried by sai rotor, extending axially thereof and interposed between sal lammations.

for induction controller appain combination, a rigid central steel web, a pluralit of axially ranged plates secured to t oipposite sides thereof and sleeves cast about e ends of said web to f nals for said rotor.

9. A removable magnetic member for induction controller apparatus, comprising in combination, a magnetic mass, and grou s of plates of electrically conductive material odied mass mounted with th d plates parallel to one another and symmetrical] on oppotiie movable 10. A rotor for induction controller a comprising in combination a ma gnetic mass and a lurality of zones of plates extending axia y along and parallel to the central plane of the magnetic member, each of said zones consisting of alternate lates of electrically conductive material an netic material.

11. A rotor for induction controller a ratus,"comprising m combination, mass. and a PP!- amagnetic plurality of zones of axial plates, said plates ing parallel with one another and with the central plane'of the rotor and each of said zones consisting of alternate plates of copper and of magnetic material.

In t fi rt h fi f A 11 1931 mname'st-aopr',

y RALPH H'lgNRY BARBOUR.

of magereunto subscribe 

